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61.
62.
P. Bonville V. Dupuis E. Vincent P. E. Lippens A. S. Wills 《Hyperfine Interactions》2006,168(1-3):1085-1089
57Fe Mössbauer spectra are presented from (H3O)Fe3(SO4)2(OH)6 (or H3O-jarosite), which is a model kagomé antiferromagnet which features geometrical frustration and spin-glass-like behaviour. Dynamic scaling of the freezing temperature as a function of frequency is observed over a large frequency range, which indicates the presence of a spin-glass transition. A fast relaxation model between “up” and “down” states, separated by an energy gap, is presented to account for the shape of the Mössbauer spectra below the freezing temperature. From a calculation of the Electric Field Gradient tensor, it is suggested that H3O-jarosite is an XY-Heisenberg antiferromagnet, where the Fe3+ moments lie in the kagomé planes. 相似文献
63.
Completely positive Markovian cocycles on a von Neumann algebra, adapted to a Fock filtration, are realised as conjugations
of -homomorphic Markovian cocycles. The conjugating processes are affiliated to the algebra, and are governed by quantum stochastic
differential equations whose coefficients evolve according to the -homomorphic process. Some perturbation theory for quantum stochastic flows is developed in order to achieve the above Stinespring
decomposition.
Received October 10, 1999 / Revised July 12, 2000 / Published online December 8, 2000 相似文献
64.
Samuel Wills 《Insurance: Mathematics and Economics》2010,46(1):173-185
Pricing and risk management for longevity risk have increasingly become major challenges for life insurers and pension funds around the world. Risk transfer to financial markets, with their major capacity for efficient risk pooling, is an area of significant development for a successful longevity product market. The structuring and pricing of longevity risk using modern securitization methods, common in financial markets, have yet to be successfully implemented for longevity risk management. There are many issues that remain unresolved for ensuring the successful development of a longevity risk market. This paper considers the securitization of longevity risk focusing on the structuring and pricing of a longevity bond using techniques developed for the financial markets, particularly for mortgages and credit risk. A model based on Australian mortality data and calibrated to insurance risk linked market data is used to assess the structure and market consistent pricing of a longevity bond. Age dependence in the securitized risks is shown to be a critical factor in structuring and pricing longevity linked securitizations. 相似文献
65.
M. Hamester D. Wiederin J. Wills W. Kerl C. B. Douthitt 《Analytical and bioanalytical chemistry》1999,364(5):495-498
A single collector double focusing sector field ICP-MS is evaluated for the determination of isotope ratios. Spectral interferences
(e.g. 40Ar23Na on 63Cu) can lead to calculation of inaccurate ratios. The use of high resolution enables such interferences to be separated from
the isotopes of interest. External reproducibilities of < 0.02% are shown for uninterfered isotopes (measured at low resolution
R = 300) and < 0.1% for interfered isotopes which required the use of medium (R = 4000) and high resolution (R = 10000).
Received: 11 January 1999 / Revised: 8 April 1999 / Accepted: 11 April 1999 相似文献
66.
The synthesis of a Tentagel-supported peptide incorporating the reactive triad of serine, histidine and aspartic acid, found within serine protease enzymes, is described. 相似文献
67.
Frost RL Wills RA Martens W Weier M Reddy BJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(1-3):42-50
A problem exists when closely related minerals are found in paragenetic relationships. The identification of such minerals cannot be undertaken by normal techniques such as X-ray diffraction. Vibrational spectroscopic techniques may be applicable especially when microtechniques or fibre-optic techniques are used. NIR spectroscopy is one technique, which can be used for the identification of these paragenetically related minerals and has been applied to the study of selected iron(II) and iron(III) sulphates. The near-IR spectral regions may be conveniently divided into four regions: (a) the high wavenumber region>7500 cm(-1), (b) the high wavenumber region between 6400 and 7400 cm(-1) attributed to the first overtone of the fundamental hydroxyl stretching mode, (c) the 5500-6300 cm(-1) region attributed to water combination modes of the hydroxyl fundamentals of water, and (d) the 4000-5500 cm(-1) region attributed to the combination of the stretching and deformation modes of the iron(II) and iron(III) sulphates. The minerals containing iron(II) show a strong, broad band with splitting, around 11,000-8000 cm(-1) attributed to (5)T(2g)-->(5)E(g) transition. This shows the ferrous ion has distorted octahedral coordination in some of these sulphate minerals. For each of these regions, the minerals show distinctive spectra, which enable their identification and characterisation. NIR spectroscopy is a less used technique, which has great application for the study of minerals, particularly minerals that have hydrogen in the structure either as hydroxyl units or as water bonded to the cation as is the case for iron(II) and iron(III) sulphates. The study of minerals on planets is topical and NIR spectroscopy provides a rapid technique for the distinction and identification of iron(II) and iron(III) sulphates minerals. 相似文献
68.
Archie Wall Alfie G. Wills Nafsika Forte Calise Bahou Lisa Bonin Karl Nicholls Michelle T. Ma Vijay Chudasama James R. Baker 《Chemical science》2020,11(42):11455
Maleimide chemistry is widely used in the site-selective modification of proteins. However, hydrolysis of the resultant thiosuccinimides is required to provide robust stability to the bioconjugates. Herein, we present an alternative approach that affords simultaneous stabilisation and dual functionalisation in a one pot fashion. By consecutive conjugation of a thiol and an amine to dibromomaleimides, we show that aminothiomaleimides can be generated extremely efficiently. Furthermore, the amine serves to deactivate the electrophilicity of the maleimide, precluding further reactivity and hence generating stable conjugates. We have applied this conjugation strategy to peptides and proteins to generate stabilised trifunctional conjugates. We propose that this stabilisation-dual modification strategy could have widespread use in the generation of diverse conjugates.An alternative approach to maleimide conjugate stabilisation is presented, by the consecutive addition of a thiol and an amine to dibromomaleimides. The amine serves to simultaneously deactivate the maleimide and enable dual functionalisation. 相似文献
69.
70.
We show analogues of Minkowski's theorem on successive minima, where the volume is replaced by the lattice point enumerator. We further give analogous results to some recent theorems by Kannan and Lovász on covering minima. 相似文献